Current solar energy thermostatic devices use methods involving temperature control set points (temperature references), and hysteresis (also referred to as differential temperature adjustment), to manage the use of solar generated heat. Thermostatic controllers, referred to as ‘on-off’ thermostatic regulators, are widely used to manage the supply of solar energy apparatus, particularly those that heat water for domestic use or to heat swimming pools. On-off regulators require temperature sensors located at the heating source as well as the supply side of the collector to regulate the flow of heated liquid based on a temperature set point and hysteresis (differential) temperature setting to control operation of the solar heating apparatus. The design of solar water heating temperature regulators focuses on excessive strain of pump motors due to constant activation and deactivation. Air mover devices (fans and blowers) for transporting solar heated air do not normally experience significant strain during operation. In solar water heating applications, temperature sensors communicate with electronic equipment to control a water pump by halting the pump motor whenever the sensed temperature drops below a reference ‘set-point’ temperature, resulting in starting the pump when temperature exceeds the temperature set point. The set-point temperature may be a directly dependent solar heating system parameter established by the user or a default setting for temperature maximum or minimum value. Examples of typical on-off regulators include U.S. Patents as follows.
Watt, U.S. Pat. No. 3,998,207 (December 1976) discloses an integrated circuit dc-comparator (a direct current voltage signal device), to control a solar water heating system for sump water and collector water temperatures such that the pump motor is deactivated when temperature exceeds a certain limit while also comparing the difference between the sump water and collector water temperatures.
Manor, U.S. Pat. No. 4,017,028 (April 1977) discloses a temperature differential sensing and control device utilizing a flexible diaphragm in contact with different regions of fluids monitored for temperature relationship resulting in the diaphragm actuating a switch to modulate and manage flow of such fluids.
Rapp, Jr. et al., U.S. Pat. No. 4,060,195 (November 1977) discloses a solar heating system circuit incorporating a solar collector, a heating load, and a heat transfer controller, including a collector valve or damper for managing the flow of heating fluid to and from the solar collector. The system incorporates a heat exchanger to accept fluid from a storage tank with the control circuit, including a load sensor, to determine temperature for purpose of switching flow of the heated fluid by actuating a heating pump.
Nurnberg, U.S. Pat. No. 4,116,219 (September 1978) discloses a differential thermostatic control, for solar heating of fluid in a solar collector and in the storage tank, for purpose of operating a pump motor. Such thermostatic control senses high and low extreme temperature to prevent excess pressure in the storage tank or freezing water in such tank.
Nurnberg, U.S. Pat. No. 4,125,107 (November 1978) discloses a universal differential thermostat for a solar heating system using a resistant bridge circuit containing connectivity as a differential comparator. Such comparator senses low-limit solar panel temperature and/or high-limit storage tank temperature for turning on or off the circulation pump or running cool water into the storage tank if necessary. Such thermostat senses a true reading of solar panel temperature through periodic operation of the water circulation pump.
Bloomfield, U.S. Pat. No. 4,184,635 (January 1980) discloses control units for heating systems utilizing a comparator device with sensors and circuitry in a cascade manner for primary and secondary sensing of temperature, where a plurality of heat stores are controlled. Differential temperature sensing with such device manages the transfer of heat from the collector to the corresponding store.
Firebaugh, U.S. Pat. No. 4,195,621 (April 1980) discloses a solid-state differential temperature regulator for a solar heating system. Such solid-state regulator has a control circuit response to temperature set point differences determined by the sensors to cause circulation of swimming pool water. A cut-off control activates valves to by-pass the solar heated water causing pool water to circulate back into the collector when temperature in the collector is lower than the pool water temperature, thus enabling cooling the pool water as a derivative operation.
Lyon et al., U.S. Pat. No. 4,313,419 (February 1982) discloses a solar heating system using a double storage device to increase efficiency and capacity over several days' operation. The system utilizes differential temperature controllers that are conventional and commercially available connected to the storage tanks to enable output from such temperature controllers to direct the flow of heated water for space heating and for domestic water heating. The system object is to provide apparent tank temperature stratification and minimum collector temperature for increased collection efficiency.
Webb, Jr., U.S. Pat. No. 4,422,444 (December 1983) discloses a solar energy control system and method for efficient use of heat produced from solar energy heating of air and/or water. Such system and methods directs heat from a solar collector to a water heater, which disperses heat into a monitored room to heat the air. When reaching the preselected temperature, the system redirects heat to water inside the water heater for reuse in heating the air in the room when required. The system provides visual display of the indicated temperature using improved probes to sense air, water and collector temperature
Wurst et al., U.S. Pat. No. 4,494,526 (January 1985) discloses a temperature sensing system for measuring differential temperature using temperature sensors placed on first and second legs of a bridge circuit. The disclosure claims three temperature sensors for solar radiation on a collector, ambient air temperature, and temperature in the fluid storage area. Using results of temperature sensing, causes a control signal to enable transfer of thermal energy by circulating fluid between the collector and storage area resulting from a comparator response to such signal.
Illing, U.S. Pat. No. 5,206,819 (April 1993) discloses a control system for a solar heater including solar collectors and a reservoir. The temperature sensor of the controller has a memory element to make periodic adjustments based on temperature and sunlight intensity. The sensor signal drifts along an equilibrium curve to enable an electronic output from the sensors to determine if the solar collectors can gain or lose heat. The device primary use is for solar water heating. The system utilizes a microcomputer to collect sensor data, store the results and evaluate the data to implement control by sending a signal to transistor hardware that operates the water pump.
Blevins, U.S. Patent Publication No. 2011/0041833 A1 (February 2011) discloses a solar heat exchanger controller used for pre-heating to support a heat pump heating system, in an air-to-air heat exchanger using solar heated fluid. The controller connects electrically to the thermostat of a conventional heating system. The controller locks out the conventional heating system operation when the solar heat is sufficient. The solar heat exchanger warms a liquid solution introducing such solution into thermal contact with saturated vapor to let refrigerant extract more heat at low ambient temperatures, allowing an air-to-air heat pump to produce its designed heating ability at lower temperatures.
The referenced U.S. Patents above reflect a common objective to enable sensing of temperatures of solar heating apparatus for purpose to manage direction of solar heated fluids through tanks or heat exchangers of the designed task including that for space heating modalities, swimming pool water heating, and domestic water heating.
The following referenced U.S. Patents are for devices that perform thermostatic functions used in traditional HVAC environmental control apparatus employing microcomputers and specialized electronic methodology within prior art modality. Such devices offer precision control of such thermostatic functions similar to the present invention thermostatic controller technology. Prior art thermostat technology includes a range of modes from elementary to elaborate in their device operating features. Many prior art devices reference improvements that allow users to perform thermostatic control functions expeditiously including ease of set point changes and for managing specialized programs that include daytime and calendar driven on-off control of the space heating operation. Many of the following patents disclose that such designs are ‘user friendly’ while some of the designs have introduced forms of intuitive thermostatic control based on a number of factors such as sleep schedules of the occupants and outside weather patterns.
Brown et al., U.S. Pat. No. 5,224,649, (July 1993) discloses a digital thermostat with single rotary encoder switch for establishing set point. The thermostat uses the encoder rotatable knob in a plurality of discrete angular positions each of which enables the switch to signal increments for purpose to change said set point of the thermostat. The encoder has temperature values imprinted on the dial for visual display through a window of the thermostat cover indicating the temperature settings from 40° F. to 90° F.
Koketsu, U.S. Pat. No. 5,236,477, (August 1993) discloses a microcomputer-based control device using non-volatile memory to store operating time of an air-conditioning control unit and power supply. The non-volatile memory overcomes issues with volatile memory types by preserving data when power disrupts. Such data includes processing information and predetermined instructions while also recording historical equipment operation time for purpose to determine time of replacement of the air filter. The device includes a DC power supply section for converting AC power to DC voltage to manage power control of fans and filter changing equipment.
Carey, U.S. Pat. No. 6,814,299 B1, (November 2004) discloses a thermostat with a one button programming feature using an LCD display and adjustment button pressed once for setback of selected temperature setting during a predetermined setback time. The device features automating date/time synchronized from the national weather broadcast station WWVB to eliminate the need for user change. The device utilizes automatic setting features preprogrammed and accessible by the user through the one button initiation directive to perform a variety of program instructions to the thermostat to fit household living habits.
Rosen, U.S. Pat. No. 6,824,069 B2 (November 2004) discloses a programmable thermostat system employing a touch screen unit for intuitive interactive interface. Such device uses a transparent touch pad over a liquid crystal display as the user interface for managing the system, which includes temperature sensor, real time clock, a central processing unit (CPU), memory coupled to the CPU for storing program and data information. The display touch screen provides for menu messages to explain function buttons and icon indicators to facility intuitive programming by the user.
McLellan et al., U.S. Pat. No. 8,091,795 B1 (January 2012) discloses an intelligent thermostat device employing an automatic adaptable energy conversation process based on real-time energy pricing. Such device displays energy demand relative to fluctuations in utility company energy prices, and then notifies the user of such fluctuations. Changes in energy pricing produces a response by such device to adjust current temperature set point by a setback based on such pricing. The device also simulates a utility meter showing the real-time energy demand. The device includes sophisticated programming for user mode selections, temperature input, and the operation of complex HVAC equipment through its energy management features.
Drees et al., U.S. Pat. No. 8,532,808 B2 (September 2013) discloses systems and methods for measuring and verifying energy savings in buildings. Such system enables historical data collected during operation for interpretation by a processing circuit to perform regression analysis of such data variables to model and predict energy usage of a building. The data processing includes weather and utility meter input which results in predictive management, including such items as baseline for heating degree-days and cooling degree-days, to help improve modeling.
Thorson et al., U.S. Pat. No. 9,108,489 B2 (August 2015) discloses a display apparatus and method having a tabbed user interface for an environmental control system. The device design focuses on the complexity of HVAC systems requiring programming and display of information such that using a tabbed presentation readout enables user flexibility to govern HVAC control with a touchscreen input device and display providing a wide range of information, including control parameters, in an organized manner. The device features significant display variables for heating and cooling with access through such tabbed selection system provided by computer programming
Shetty et al., U.S. Pat. No. 9,115,908 B2, (August 2015) discloses systems and methods for managing a programmable thermostat. The devices contains a management profile to include a data acquisition and data analysis subsystem that works in conjunction with user programmed settings to eliminate waste of energy. User input includes a wide assortment of program parameters for temperature set point, sensing of relay states, and season/date/time oriented parameters (day, wake, away, return, and sleep, for example). The data acquisition mode includes acquiring energy usage from a utility company.